<?php
class MathCaptchaAction extends CCaptchaAction
{
	protected function generateVerifyCode(){
		return mt_rand((int)$this->minLength,(int)$this->maxLength);
	}
	
	public function renderImage($code){
		parent::renderImage($this->getText($code));
	} 
	
	protected function getText($code){
		$code = (int)$code;
		$rand = mt_rand(1, $code-1);
		$op = mt_rand(0, 1);
		if($op)	
			return $code-$rand.'Plus'.$rand.'=';
		else
			return $code+$rand.'Minus'.$rand.'=';
	}
}

